Prepare the shawarma sauce first, so the flavors have time to blend. Stir together the yogurt garlic, lemon juice, oregano, salt, cinnamon, nutmeg, and cloves in a bowl. Set the sauce aside.
Begin to preheat the oven to 400ºF. Wash the potatoes, then cut them into wedges. Place them on a large baking sheet so they are in a single layer with at least a small amount of room around each piece.
Drizzle the olive oil over the potatoes, then add the garlic powder, oregano, salt, and pepper. Toss the potatoes until they are well coated in the oil and spices.
Roast the seasoned potatoes in the oven for 30-35 minutes, stirring 2-3 times throughout, or until they are golden brown on all sides.
While the potatoes are in the oven, roughly chop the parsley and crumble the feta. After roasting the potato wedges, remove them from the oven, drizzle the shawarma sauce over top, and then sprinkle the parsley and feta over everything.